So you will let someone live their lives for 18 years, and then if they can't do something to benefit society, then we kill them? They would still be a "burden" for 18 years, the people that care for them and know them will gain attachment. All this is going to do is make people who want to keep their children (because of this weird thing called love) into criminals because they will obviously try to find a way to hide them.

Even assuming everyone was willing to kill these 18 year olds. What about other people that require assistance to live their lives? What about people without limbs? Surely they, too, are "burdens" on society.

We should also murder people who aren't tall, because they ruin the gene pool. I'm 6'0, so I'm good. I'm not so sure about you.

It's not.
I didn't say anything about killing anyone, euthanizing something is different (also this is supposed to happen in the future-to-come, excluding our own lifetimes, respectively).
Also remember when you cherry-picked earlier and instead of you taking away the fact that I said don't contribute anything to society, you went on with a list about famous people that have obviously contributed something that had mental disorders?

It's not cherry picking when you say "Mentally challenged people haven't contributed anything to society" and I give you a list of people that have contributed to society and are mentally disabled. That is called proving you wrong.

So you will let someone live their lives for 18 years, and then if they can't do something to benefit society, then we kill them? They would still be a "burden" for 18 years, the people that care for them and know them will gain attachment. All this is going to do is make people who want to keep their children (because of this weird thing called love) into criminals because they will obviously try to find a way to hide them.

Even assuming everyone was willing to kill these 18 year olds. What about other people that require assistance to live their lives? What about people without limbs? Surely they, too, are "burdens" on society.

We should also murder people who aren't tall, because they ruin the gene pool. I'm 6'0, so I'm good. I'm not so sure about you.

It's not.
I didn't say anything about killing anyone, euthanizing something is different (also this is supposed to happen in the future-to-come, excluding our own lifetimes, respectively).
Also remember when you cherry-picked earlier and instead of you taking away the fact that I said don't contribute anything to society, you went on with a list about famous people that have obviously contributed something that had mental disorders?

It's not cherry picking when you say "Mentally challenged people haven't contributed anything to society" and I give you a list of people that have contributed to society and are mentally disabled. That is called proving you wrong.

I could go on for pages, this is just a very small amount of people that I picked out from a quick good search. OP says that people who are "mentally challenged" should be murdered. Well, at what point do we murder them? Before or after they make great contributions to the world?

Also, he's started backpedaling saying that he only means people who are dependent on other people to survive and take care of them. Still, that would include some of the greatest people in the world. The first that comes to mind is Stephen Hawking.

So you will let someone live their lives for 18 years, and then if they can't do something to benefit society, then we kill them? They would still be a "burden" for 18 years, the people that care for them and know them will gain attachment. All this is going to do is make people who want to keep their children (because of this weird thing called love) into criminals because they will obviously try to find a way to hide them.

Even assuming everyone was willing to kill these 18 year olds. What about other people that require assistance to live their lives? What about people without limbs? Surely they, too, are "burdens" on society.

We should also murder people who aren't tall, because they ruin the gene pool. I'm 6'0, so I'm good. I'm not so sure about you.

It's not.
I didn't say anything about killing anyone, euthanizing something is different (also this is supposed to happen in the future-to-come, excluding our own lifetimes, respectively).
Also remember when you cherry-picked earlier and instead of you taking away the fact that I said don't contribute anything to society, you went on with a list about famous people that have obviously contributed something that had mental disorders?

It's not cherry picking when you say "Mentally challenged people haven't contributed anything to society" and I give you a list of people that have contributed to society and are mentally disabled. That is called proving you wrong.